Christoph ReinhartL07 Daylighting Design Guidelines

4.401/4.464 Environmental Technologies in Buildings

Massachusetts Institute of TechnologyDepartment of ArchitectureBuilding Technology Program

Rules of Thumb

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Lighting Module Light and Human Vision Daylighting Design Principles Daylight Simulations & Metrics Visual Comfort Electric Lighting

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Weekly Reading And TutorialsChapter 2: Designing for DaylightChapter 5: Massing Studies

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What is daylighting?

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Daylighting is the act of lighting the interior and/or exterior of a building with natural daylight.

Generic Definition of Daylighting

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Default solution until the 1940s.

1st renaissance during the 1970s primarilyto save energy.

2nd renaissance since 2000, light aselement of more healthy and productivework spaces.

Brief History of Daylighting

MIT Chapel by Eero Saarinen, 1955 (Photo courtesy of Freshwater2006 on Flickr. License: CC BY-NC)

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Five Daylighting Definitions1: The interplay of natural light and building form to provide a visually stimulating, healthful, and productive interior environment

2: The replacement of indoor electric illumination needs by daylight, resulting in reduced annual energy consumption for lighting

3: The use of fenestration systems and responsive electric lighting controls to reduce overall building energy requirements (heating, cooling, lighting)

4: Dynamic control of fenestration and lighting to manage and control building peak electric demand and load shape

5: The use of daylighting strategies to minimize operating costs and maximize output, sales, or productivity Definitions courtesy of S. Selkowitz

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What do your peers think?

177 Participants (over 80% using LEED)Paper: Galasiu A D, Reinhart CF, “Current Daylighting Design Practice: A Survey,” BuildingResearch & Information 36:2 pp. 159 – 174, 2008.

Survey of 177 design practitioners

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Five Daylighting DefinitionsArchitectural definition: The interplay of natural light and building form to provide a visually stimulating, healthful, and productive interior environment

Lighting Energy Savings definition: The replacement of indoor electric illumination needs by daylight, resulting in reduced annual energy consumption for lighting

Building Energy Consumption definition: The use of fenestration systems and responsive electric lighting controls to reduce overall building energy requirements (heating, cooling, lighting)

Load Management definition: Dynamic control of fenestration and lighting to manage and control building peak electric demand and load shape

Cost definition: The use of daylighting strategies to minimize operating costs and maximize output, sales, or productivity Definitions courtesy of S. Selkowitz

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How would you define a well daylit space?

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Balanced

Doe Library at UC Berkeley 1911, Architecture: Émile Bénard. Photo courtesy of Mark Pritchard on Flickr. License: CC BY-NC-SA.11

Daylight from several orientations

Public domain photo by Abby Rowe, National Park Service, courtesy of Harry S. Truman Library.

© Agoda.com. All rights reserved. This content is excluded from our Creative Commons license. For more information, see https://ocw.mit.edu/help/faq-fair-use/.

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Contrast

Church of Light, 1989, architecture Tadao Ando. Photo courtesy of Naoya Fujii on Flickr. License: CC BY-NC.

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Existential Quality

Drawing courtesy of Jeff Niemasz. Used by permission.14

Passing of Time

Museu d'Art Contemporani de Barcelona by Richard Meier. Photo © MACBA. All rights reserved. This content is excluded from our Creative Commons license. For more information, see https://ocw.mit.edu/help/faq-fair-use/.

Lightshelf toreduce contrast atground level

White walls are acanvas for daylight

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Thermal Baths, Vals, Peter Zumthor. (Photo courtesy of Marco Pozzo on Flickr. License: CC BY-NC-SA.)

Hidden Openings

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Adding Color

Chapel of St Ignatius, 1997 Seattle, Washington by S. Holl. (Left: photo courtesy of MichelleMarie on Flickr. License: CC BY-NC. Right: photo © Seattle University. All rights reserved. This content is excluded from our Creative Commons license. For more information, see https://ocw.mit.edu/help/faq-fair-use/.)

Indirect, reflected daylight, the back side of theilluminated wall is yellow Daylight = architectural concept

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Treasury of Atreus in Mycenae, Greece, 1250 BC. (Photo courtesy of Richard on Flickr. License: CC BY-NC-SA)

Light and Darkness

https://www.amazon.com/Praise-Shadows-Junichiro-Tanizaki/dp/0918172020/ref=nosim/mitopencourse-20

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Dramatic Proportions

Redwood forest near Humboldt, California (Photo courtesy of Jeff Myers on Flickr. License: CC BY-NC.)

Basilica di Sagrada Familia, Gaudi, 1882, Barcelona, Spain. (Photo courtesy of Melissa Delzio on Flickr. License: CC BY-NC.)

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Framework for High-Performance Façade Analysis

Paper: C F Reinhart and J Wienold, "The Daylighting Dashboard - A Simulation-Based Design Analysis for Daylit Spaces," Building and Environment, 46:2, pp. 386-396 (2011).

Visual Comfort

Daylight Availability

Occupant BehaviorControls

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Manual Control

Photo courtesy of Kristin Roach on Flickr. License: CC BY-NC-SA.21

Automated Controls

Rolex Center, Lausanne, Switzerland, Architecture Sanaa

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Architectural Control

New York Public Library, Architecture Carrère and Hastings23

Adaptive Control

Rolex Center, Lausanne, Switzerland, Architecture Sanaa

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Framework for High-Performance Façade Analysis

Paper: C F Reinhart and J Wienold, "The Daylighting Dashboard - A Simulation-Based Design Analysis for Daylit Spaces," Building and Environment, 46:2, pp.

386-396. (2011)

Visual Comfort

Daylight Availability Energy

Occupant BehaviorControls

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Metrics

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Metric Hunting

Summer 2007 - Daylighting Metrics Study: “The degree of agreement between theexperts was surprising given that the same individuals tend to frequently disagreewhen it comes to the development of quantitative performance metrics of imaginarydaylit spaces.” In contrast, daylight factor predictions are much more divergent.

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MIT Reference Office

The reference office represents a south-facing sidelit office located in Boston. The officeis not obstructed by neighboring buildings.

The large room depth of 8.2 m, which corresponds to nearly 3.5 times the floor toceiling height, was consciously chosen to be rather large so that the effect of differentdaylighting strategies remains visible for all variants.

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MIT Reference Office

You may think of the reference office as one of several identical spaces in abuilding.

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Dashboard Reference Office

Located in Boston30

Design Tools

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Daylighting Design ToolsPe

rcen

tage

of P

artic

ipan

ts [%

]

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Toward a Fruitful Relationship between Simulations, Rules of Thumb, and Physical Model Testing

Energy

Rules of Thumb

Rules of ThumbSimulation Physical Model Testing

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Daylight Availability Studies

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Framework for High-Performance Buildings

Visual Comfort

Daylight Availability Energy

Occupant BehaviorControls

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What is the relationship between daylight availability and building massing, i.e. how much

of a building can be daylit depending on its overall shape and surrounding context?

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What is the Daylit Area?

How can we determine the daylit area in a space?

We will be looking at three related approaches.37

(1) Based on Daylight Autonomy

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Daylight Autonomy

Daylight autonomy (DA) is a daylight availability metric thatcorresponds to the percentage of the occupied time when thetarget illuminance at a point in a space is met by daylight.39

(1) Based on Daylight Autonomy

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Daylight Autonomy by Climate

Daylight autonomy is climate-dependent but not too much. It has been adoptedby the IESNA LM-83 which now in turn is being using by LEED v3.0.

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Varying Daylight Autonomy Distributions across 186 sites in North America

dynamic interaction of light and building form

186 sites representing 74% of the US and 63% of the Canadian population.42

Varying Daylight Autonomy Distributions across the 186 Sites for a South-facing Office

dynamic interaction of light and building form

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Varying Daylight Autonomy Distributions across the 186 Sites for a South-Facing Office

dynamic interaction of light and building form

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dynamic interaction of light and building form

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Significance of Internal Partitions

Paper: Reinhart C F, "Effects of interior design on the daylight availability in open plan offices."Proceedings of the ACE3 2002 Summer Study on Energy Efficiency in Buildings, 14 pp., Pacific Grove,USA, August 2002.

(1m)

(1.5m)

(2m)

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When you are close to a window, what are the most important surface properties that determine

the daylight near you?

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dynamic interaction of light and building form

Visual light transmittance of the window48

Visual Transmittance (τ): Fraction of incident visible radiation that reaches theinterior.49

How would you measure this?

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When you are deeper in a sidelit space, what are the three most important surfaces that determine

how deep daylight enters a building?

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dynamic interaction of light and building form

Outside ground reflectance Visual light transmittance of the window Ceiling reflectance

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dynamic interaction of light and building form

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dynamic interaction of light and building form

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How would you measure this?

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OK, that’s what the computer tells us.How well do daylight autonomy (and other

daylight availability metrics) relate to occupant assessments of spaces?

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Daylit Area Exercise

Paper: C F Reinhart and D Weissman, "The Daylit Area - Correlating architectural student assessments with current and emerging daylight availability metrics," Building and Environment, 50, pp. 155-162, 2012.

“A key architectural concept is to divide the floor plan of a building or space into a ‘daylit’ and a ‘non-daylit’ area. Within the daylit area indoor

illuminance levels due to natural light should be adequate, useful and balanced for most of the year. In this exercise you are asked to follow your own intuition and divide [name of study space] into a daylit and a non daylit area. Please visit the [name of study space or spaces on date and time range] and

individually conduct your assessment without consulting with the other students.”

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Photos courtesy of Dan Weissman. Used with permission.

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Carpenter Center Study

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Carpenter Center Study

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Partially Daylit Area

Mean Occupant Assessment

Instead of a hard line between daylit and non-daylit we arelooking for a transition, partially daylit area.

How well does this work?

Partially Daylit Area

Between 25% and 75% of studentsvoted that the area is ‘daylit’.

Spatial Daylight Autonomy DA150lux >50%

Fully Daylit Area

Over 75% of students voted that the area is ‘daylit’.

Spatial Daylight Autonomy DA300lux >50%

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What is the Daylit Area?

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Carpenter Center Study

Student assessments sDA 300 lux simulations

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Lorax Project Daylight Area Study II

Daylight Autonomy300lux[50%]

Mean Occupant Assessment

Supported by MIT HASS Collaboration with Tarek Rakha and Dan Weissman

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Lorax Project Participants

Daylight Autonomy300lux[50%]

Mean Occupant Assessment

HarvardMIT

Miami UniversityUSC

University of Idaho

Concordia University

Federal University of Paraiba

Ain Shams University

Santa Catarina

Iowa State

Parsons

Base layer of map © Google. All rights reserved. This content is excluded from our Creative Commons license. For more information, see https://ocw.mit.edu/help/faq-fair-use/.

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MIT - I Christoph Reinhart, Spring 2012 18 Participants – Clear

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MIT - I

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MIT - I

DA_150 lux

DA_300 lux

Simulation Student Responses

Note that student responses correlated with architectural features such aswalls and corners.

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MIT - II 18 Participants – Clear

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MIT - II

DA_300 lux

DA_150 lux

Simulation Student Responses

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Miami University

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Miami University Mary Ben Bonham, Spring 2012 35 Participants – Overcast

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Miami University

DA_300 lux

DA_150 lux

Simulation Student Responses

Only toplit space.

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Result OverviewC F Reinhart, T Rakha and D Weissman, "Predicting the Daylit Area — A Comparison of Students Assessments and Simulations at Eleven Schools of Architecture," LEUKOS, 1pp. 193-206, 2014. Version: Author's final manuscript. License CC BY-NC-SA.

https://dspace.mit.edu/handle/1721.1/106323.

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Study Conclusions

Daylight Autonomy300lux[50%]

Mean Occupant Assessment

Encouragingly good agreement with new IESNA SpatialDaylight Autonomy predictions.

Support the use of Spatial Daylight Autonomy as proposedby LEEDv3.

Surprising since people cannot see illuminances and it is unlikely that they can predict how a space will look during different times of the year.

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Rules of Thumb

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Window-Head-Height Rule of ThumbReinhart, Building Simulation 2005

Mantra in sustainable design Sole quantitative justification for room proportions/façade design An empirical rule

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Parameter StudyVariable Range

climatescenters

Daytona Beach, FL

L.A.,CA

New York, NY

Vancouver, BC

Winnipeg, MB

facadeorientation

North South West East

t window[%]

35 75

balustrade yes no

sill yes no

occupancy office classroom

min ill.[lux]

300 500

window head height identical in all 640 cases83

Window-Head-Height Rule of Thumb

Frequency distribution of daylight penetration depths.

Reinhart, Building Simulation 2005

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Window-Head-Height Rule of Thumb

In a sidelit space with a standard window and venetian blinds, the depth of the daylit area usually lies between 1.5 and 2 times the window-head-height.

If a space does not require the use of a shading device the ratio range can increase up to 2.5.

Reinhart, Building Simulation 2005Paper: Reinhart C F, “A simulation-based review of the ubiquitous window-head-height to daylit zonedepth rule of thumb,” Building Simulation 2005, Montreal, Canada, August 15-18 2005.

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Daylit Area (for Massing Studies)

Daylit Area (2 times the window head height)

Non-Daylit Area

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Case Study: Daylight Availability Study Puerto Rico

© by two anonymous MIT students. All rights reserved. This content is excluded from our Creative Commons license. For more information, see https://ocw.mit.edu/help/faq-fair-use/.

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Neighboring Obstructions

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Parametric Study

Parametric study to evaluate the effect of neighboring building on interior daylitavailability. A total of 2304 spaces.

Paper: Reinhart C F and V R M LoVerso, "A Rules of Thumb Based Design Sequence for Diffuse Daylight," Lighting Research and Technology, 42:1, pp.7-32 (2010).

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External Obstruction

dynamic interaction of light and building form

The effect of neighboring building on a sidelit space in a one- or two-story building is low (and can even be positive for north facing facades) for obstruction angles smaller than 30o.

Low Target Building

α= obstruction angle

q = sky angle angle

a q

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Daylight Feasibility Test

WWR>2000θ91

Design Sequence for Diffuse Daylighting(1) Urban Project(2) Come up with an initial

Design Variant(3) Divide Building into Zones

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Definition of Sky Angle

θ

The reference point on the façade is the glazing center.

θ = 60o

θ = 25o

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Carry out a daylight feasibility test for eachzone. Cutoff level for the WWR is about80% (fully glazed façade). Continueanalysis for zones that pass the daylightfeasibility test and revise yourdesign/expectations accordingly.

Daylight Feasibility Test

WWR > 33%

WWR > 80%

Pass

Fail Note: At this point you should start to adapt your design.

WWR> 2000θ

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Atrium Rule of Thumb

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Massing Study

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Considering Urban Context

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Is it really that easy? Rules of thumb indicate the daylight potential of a massing. Things can stillgo wrong, but if the rules suggest limited potential, the likelihood is high that anydaylighting strategies applied later in the design process will have limited effect.

Rules of thumb can be used as formgivers. Then simulations can be used torefine design concepts. Rules may also be used for quality control.

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Rules of Thumb as Formgivers

Image courtesy of Jeff Niemasz. Used by permission.100

Skyl

ight

s

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Paper: T Dogan and C F Reinhart, “Urban daylight simulation: Calculating the daylit area of urban designs,” Proceedings of SimBuild 2012, Madison, Wisconsin, USA

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New York Zoning Revisited

This image is from M Saratsis, T Dogan and C F Reinhart, “Simulation-based daylighting analysis procedure for the development of urban zoning rules,” Building Research and Information, 45:5, pp. 478-491, 2017. This journal is available online at https://www.tandfonline.com/doi/full/10.1080/09613218.2016.1 159850

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LM83/LEED vs zoning regulationsSp

atia

l Day

light

Aut

onom

y

$1 billion in additionalreal estate

This image is from M Saratsis, T Dogan and C F Reinhart, “Simulation-based daylighting analysis procedure for the development of urban zoning rules,” Building Research and Information, 45:5, pp. 478-491, 2017. This journal is available online at https://www.tandfonline.com/doi/full/10.1080/09613218.2016.1159850.

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Conclusions We discussed three complementary approaches to predict the daylight

availability in buildings:1. Daylight Autonomy Simulation-Based2. Based on Occupant Assessments3. Based on Rules of Thumb

Occupant assessments largely support simulation results.

Derived rules of thumb set can be used for massing studies.

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Design Guidelines

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Architectural Considerations Introduce setbacks on higher floors to increase the

sky access for lower levels. If possible, reduce floor plan depth to less than 5-7

times the floor to ceiling height to maximize thedaylit area.

Open up the building through atria, windows,skylights, and clerestories.

Place window as high as possible near the ceiling. Create a view to/from the outside. Use the daily and seasonal variations of daylight to

enhance visual interest. High surface reflectances make rooms appear

larger; a vertical/horizontal window near a brightwall/ceiling makes a room appear wider/higher. dynamic interaction of light and building form

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Occupant Comfort and Well-Being Use daylight for full spectrum color rendering. Balance a view to the outside with occupants’

privacy (perforated shades). Avoid low solar angles onto facades. Maintain daylighting levels within acceptable

limits. Develop a suitable shading device strategy

(shading from neighboring buildings, venetianBlinds, light shelves).

Avoid work places too close to exterior glazings.

workspace with high visual comfort

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Questions?

www.daylight1-2-3.comwww.daysim.com

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